1. Field of the Invention
The present invention relates to an apparatus for eluting impurities from a substrate. More particularly, the present invention relates to an apparatus for eluting impurities from a semiconductor substrate to produce a liquid sample by which impurities in the substrate can be analyzed.
2. Description of the Related Art
Generally, a semiconductor device is manufactured by performing a fabrication (FAB) process for forming an electric circuit on a semiconductor substrate comprising a silicon wafer, an electrical die sorting (EDS) process for inspecting electrical characteristics of the electric circuit, and a packaging process for separating the semiconductor substrate into individual semiconductor chips and sealing each of the semiconductor chips using an epoxy resin. The FAB process includes a deposition process for forming a thin layer on the semiconductor substrate, a CMP process for chemically and mechanically polishing the thin layer, a photolithography process for forming a photoresist pattern on the thin layer, an etching process for etching the thin layer into an electrical pattern using the photoresist pattern as a mask, an ion implantation process for implanting ions into a predetermined region of the semiconductor substrate, a cleaning process for cleaning impurities from the semiconductor substrate, and an inspection process for inspecting a surface of the semiconductor substrate so as to detect defects in the thin layer or pattern.
The impurities, such as metallic contaminants, usually reduce the yield and performance of the semiconductor devices. Therefore, a great deal of importance has been placed on the inspection process as a means to improve the yield and performance of semiconductor devices, especially in the case of semiconductor devices having a high degree of integration.
The inspecting process analyzes impurities in an upper layer of the semiconductor substrate. To this end, the inspecting process includes an extraction process for extracting a sample containing the impurities, and an analysis process for analyzing the sample. An exemplary apparatus for and method of extracting such a sample are disclosed in U.S. Patent Publication No. 2002-134406. According to U.S. Patent Publication No. 2002-134406, the apparatus for extracting the sample includes a closed processing chamber, a loading/unloading unit for loading/unloading a wafer into/from the chamber, a vapor decomposing unit disposed inside the processing chamber for decomposing a silicon oxide layer on a wafer disposed in the chamber, and a scanning unit disposed inside the processing chamber for scanning the wafer.
Meanwhile, U.S. Pat. No. 6,519,031 (issued to Gilton et. al.) discloses a surface analysis device for obtaining a sample from a predetermined local portion of a wafer by dissolving an isolated portion of the wafer in an eluant comprising an etching solution or a solvent such as an organic solvent. The sample so obtained includes various impurities. The impurities are analyzed using a destructive analysis device such as an atomic absorption spectroscope or an inductively coupled plasma (ICP)-mass spectroscope, and a non-destructive analysis device such as a total X-ray fluorescent analyzer.
The extraction apparatus disclosed in U.S. Patent Publication No. 2002-134406 may be suitable when the surface of the semiconductor substrate is hydrophobic, and the surface analysis device disclosed in U.S. Pat. No. 6,519,031 (issued to Gilton et. al.) may be suitable when the surface of the semiconductor substrate is hydrophilic.
However, the prior art surface analysis device is disadvantageous in that it cannot produce a sample from many local regions of the wafer surface simultaneously and hence, the analysis process requires a great amount of time to complete. In addition, the prior art surface analysis device has inner and outer tubes for extracting samples when numerous local regions of the wafer surface are to be analyzed. The surface analysis device sequentially analyzes the local regions of the wafer surface in order via the inner and outer tubes. However, the use of the inner and outer tubes may render the analysis process unreliable.